BOISE, Idaho (AP) -- A federal judge says prosecutors failed to prove allegations that a southern Idaho feedlot manager discharged fluids into the aquifer that were contaminated with manure and bacteria. U.S. District Judge B. Linn Winmill issued the ruling Monday in the case of Cory King, manager of Double C Farms near Burley. King was convicted by a jury in April of four counts of discharging fluids into the aquifer without a permit in 2005 and one count of lying to a state investigator. He is scheduled to be sentenced next month, but the judge's latest ruling will play a key role in the sentencing. At a hearing earlier this month, federal prosecutors argued the fluids diverted into the groundwater were tainted with manure. But Winmill concluded that water samples presented by prosecutors failed to prove contamination.